The invention is directed to a process to prepare a hydrogen rich gas mixture from a halogen containing gas mixture comprising hydrogen and at least 50 vol. % carbon monoxide, on a dry basis.
EP-A-1939138 describes a process wherein a hydrogen and halogen containing gas rich in CO is subjected to a water gas shift reaction. In this process the gas is first subjected to a water scrubbing step to remove the halogen compounds from the gas. Subsequently part of the scrubbed gas is contacted with liquid water having a temperature of below the saturation temperature of water. After adding additional steam the gas is used as feed to the water gas shift reaction. The molar ratio of steam to carbon monoxide in said feed is preferably about 2.8:1 according to this publication.
A disadvantage of this process is that a complex process line-up is required to increase the steam content in the gas as fed to the water gas shift reaction step. There is a desire for a more efficient process. The following process provides such a more efficient process.